For months, tensions have been growing within the Senate Republican conference over Sen. Jim DeMint’s (R-SC) increasingly brash assertion of authority in opposition to the party leaders. Through his Senate Conservatives Fund, DeMint has spent millions backing tea party candidates to run against those endorsed by the GOP establishment in Republican primaries, and has asserted himself in Washington by abusing Senate rules. It now appears these intra-party tensions have come to a head.

Last week, in a fundraising email to supporters, DeMint accused his colleagues of doing “everything” in their power to help Sen. Lisa Murkowski’s (R-AK) write-in campaign against Joe Miller, the GOP nominee whom DeMint supported during the primary over opposition from mainline Republicans. The email discussed a closed-door meeting in which Republicans decided to allow Murkowski to keep her ranking member position on the Senate energy committee. In interviews with Politico, a number of leading Republican senators offered rare public rebukes of their colleague, accusing Demint of “intensifying a rift within a party that’s trying to unite,” and of breaching protocol by discussing the closed-door meeting:

— “I personally think it’s very counterproductive,” said retiring Sen. Kit Bond (R-MO), calling the attack, “totally inaccurate.” Bond “scoff[ed] at what he and other GOP senators see as DeMint’s apparent attempts to build his national profile at the expense of his colleagues.”

— “I would take issue with that,” said Sen. John Thune (R-SD), the number four Senate Republican and likely 2012 presidential candidate. He said DeMint’s statements are “overstating what happened. I think the Republican leadership is very much doing everything they can to help the Republican nominee in Alaska.”

— Sen. Lamar Alexander (R-TN), the GOP conference chairman, chided DeMint for publicizing the closed-door meeting, saying, “Our strong tradition in the Republican Conference is to have a free and open exchange and to keep that among ourselves.” “I’m always disappointed when some member of our conference decides not to follow that tradition. It makes it hard for us to be a team,” he continued.

In response, DeMint remained defiant. While admitting he may have been “perhaps overly aggressive” in the email, DeMint said, “I’m ready to take on those critics because I’m giving my full support to all the Republicans, and I’m not sure that all Washington Republicans are getting behind our candidates.” “I hate to offend my colleagues,” DeMint told Politico, “but the fact is that there is a battle going on for the heart and soul of the Republican Party.”